As is well known, an analog-to-digital converter (ADC) is used for converting the amplitude of an analog voltage (or current) into a digital value. Moreover, the analog-to-digital converter (ADC) has various circuitry configurations. According to the circuitry configurations, the analog-to-digital converters include a flash analog-to-digital converter (flash ADC), a pipeline analog-to-digital converter (pipeline ADC), a successive approximation analog-to-digital converter (SAR ADC), and so on.
Generally, the flash ADC is operated at the highest rate. However, the flash ADC has a complicated circuitry configuration and higher fabricating cost. The SAR ADC is operated at a slower rate. However, the SAR ADC has a simplified circuitry configuration and lower fabricating cost.